fn multiply(first_number_str: &str, second_number_str: &str) -> i32 {
    let first_number = first_number_str.parse::<i32>().unwrap();
    let second_number = second_number_str.parse::<i32>().unwrap();
    first_number * second_number
}

fn main() {
    println!("Hello, world!");

    let twenty = multiply("10", "2");
    println!("double is {} ", twenty);

    let tt = multiply("tt", "2");
    println!("double is {}", tt);
}
